Can Chickens Live on Grass Alone? Debunking the Pasture-Fed Poultry Myth
Chickens lack teeth, salivary enzymes to tackle cellulose, and the multi-chambered fermentation vats found in cows or goats. When a hen snips off a tender shoot of Kentucky bluegrass, that vegetation moves down the esophagus and pauses inside the crop, a storage pouch at the base of the neck. Food softens there before descending into the proventriculus, the chemical stomach, and then into the gizzard.
The gizzard serves as the bird's mechanical grinder. Muscular walls contract forcefully, using swallowed stones and insoluble poultry grit to crush ingested material into a paste. If that material consists of tender young shoots, the gizzard processes it smoothly.
Problems arise with crude fiber intake. Once pasture plants mature, their structural walls thicken with insoluble lignin and structural cellulose. A chicken’s paired ceca, blind pouches located at the junction of the small and large intestines, host microflora that carry out slight fermentation, but their capacity is minimal. Studies in poultry nutrition show that high-fiber diets accelerate gut transit time while depressing nutrient absorption. When a hen's digestive system fills with fibrous green matter, the bird feels physically full while starving for usable metabolizable energy and absorbable amino acids.
